Breast cancer is the leading cause of death for women between the ages of 35 and 50. There will be 175,000 new cases of breast cancer diagnosed in the United States in 1991, and approximately 45,000 deaths from the disease. New approaches to diagnosis, prevention, and treatment are desperately needed. Over the past few years, great strides have been made in identifying critical genetic elements, including oncogenes and tumor suppressor genes, whose aberrant expression may contribute to the pathogenesis of breast cancer. Similarly, there is a wealth of new information about specific growth factors, growth factor receptors, cell surface molecules and proteases whose expression is associated with breast cancer cell proliferation, invasiveness, and metastasis. The breast cancer field has now reached a stage where it is important to develop a synthesis of these new molecular insights into disease causation, preferably with input from clinicians, epidemiologists, geneticists and molecular biologists. The multidisciplinary meeting at Cold Spring Harbor Laboratory will provide a unique opportunity for such a synthesis and will enable investigators to explore the various ways that this new information can be exploited clinically, for improved disease diagnosis, prevention, and treatment.